病重的母亲死于火灾,令乖乖女安娜(埃米莉·勃朗宁 Emily Browning 饰)备受打击,甚至企图自杀。经过一段时间的精神康复,安娜获准回到阔别已久的家中,那里有她身为作家的父亲史蒂芬(大卫·斯特雷泽恩 David Strathairn 饰),亲密无间的妹妹爱丽克丝(阿莉尔·凯贝尔 Arielle Kebbel 饰)以及令她不知该如何对待的未来继母——妈妈曾经的护士蕾切尔(伊丽莎白·班克斯 Elizabeth Banks 饰)。在此期间,安娜接连看到母亲凄惨恐怖的身影,好友马特(Jesse Moss 饰)则声称见到了火灾当晚的一切。种种迹象表明,安娜的母亲并非死于意外,姐妹俩自然而然将凶手锁定在蕾切尔的身上。 未过多久,马特遇害。阴云重新笼罩在安娜一家人的头顶。这个可怜几近崩溃的女孩,在真实和虚幻之间彷徨失措……After the death of her ill mother in a fire, the young teenager Anna tries to commit suicide and is sent to a mental institution for treatment. Ten months later, Anna still cannot remember what had happened on the night her mother died. Her psychiatric Dr. Silberling, however, discharges her telling that she has resolved her issues. Her father and successful writer, Steven, brings her back home in an isolated mansion nearby the coast. Anna finds that her mother's former nurse, Rachel Summers, is her stepmother now. Anna meets her beloved sister, Alex, swimming in the sea. She discovers that Steven has not delivered the letters and CDs that Alex had sent to her. As time moves on, Anna is haunted by ghosts and she believes that Rachel killed her mother. Alex and Anna decide to look for evidence to prove that Rachel is the murderer and Anna discovers the truth about the fire in the boat house.